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Understanding Speaker Measurements (Video)

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amirm

amirm

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"speaker is compressing" is a suspicious line that gets used frequently in guitar amp discussions online. I'd love to see some measurements (or solid arguments) proving or disproving it.
Its electronic counterpart is easy to see in a number of my reviews:

index.php
 

ROOSKIE

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"speaker is compressing" is a suspicious line that gets used frequently in guitar amp discussions online. I'd love to see some measurements (or solid arguments) proving or disproving it.
Hi, speakers compress. I am not aware of exceptions but I suppose there are some designs that don't.
In any case it is quite easy to demonstate for yourself with some basic measurement gear and a mic and REW.
Honestly you can likely hear it easily if you are willing to really turn up a pair of bass limited speakers.

Erins Audio Corner, has some reviews where he shows a type of compression with the data clearly presented. That data is not even a worse case senario as it is only a sweep and not multiple frequencies being played at once. Even in a simple sweep you can see some speaker compressing a lot.
I should note that as the voice coil heats up the driver TS parameters actually change and so does system bass frequency tuning so not all compression in the bass is due to limitation, some is simply frequency responce difference due to the fluid nature of the TS parameters.

Nearly any decent box tuning program can simulate the changes in system tuning with respect to VC temperature changes.
 

Astoneroad

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Without this vid, or Amir's tutorial on how to speed read DAC measurements, I would have never known this information. That's pretty amazing, if you think about it. Amazing that in under 2 hours, I've learned more audio facts than I have in 40 years of swimming in the shallow gene pool that is the world of audio perception. You mentioned your intention to do a tutorial on measuring the room with a mic and REW... YES PLEASE. Thanks Amir.
 
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AdamG

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Without this vid, or Amir's tutorial on how to speed read DAC measurements, I would have never known this information. That's pretty amazing, if you think about it. Amazing that in under 2 hours, I've learned more audio facts than I have in 40 years of swimming in the shallow gene pool that is the world of audio perception. You mentioned your intention to do a tutorial on measuring the room with a mic and REW... YES PLEASE. Thanks Amir.
Exciting Right? Amir’s Videos are incredibly informative. The old quote comes to mind:

“Give a person a Measurement, and you feed their brain for a day. Teach the person to Measure, and feed their brain for a lifetime”
 

Timcognito

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Exciting Right? Amir’s Videos are incredibly informative. The old quote comes to mind:

“Give a person a Measurement, and you feed their brain for a day. Teach the person to Measure, and feed their brain for a lifetime”
Or this one, One test is worth a thousand expert opinions. That one was on the tensile testing machine in the testing lab where I worked as a tech and machinist to to pay for college.
 

audiofooled

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Per popular demand, I recorded a long (1 hour) video on how to read speaker measurements but also, the underlying research (and physics) that mandate some of those concepts. Also covered is equalization and listening tests (briefly). As usual, my videos are "one take" directly recorded and uploaded (and in this case, with no reharsal). So please take it easy as far as critiquing it in that regard. :)


A personal note: as you all know, I don't allow advertising in my videos, nor do I pester people to subscribe, give likes, etc. in the video. Alas, it seems some out there are keeping score on popularity of my content as proof point of whether their audio videos are more correct than mine. So let's even the playground and subscribe to my channel if you have not before. Click on this link to go to my youtube channel (youtube.com/@audiosciencereview) and do that. Appreciate it in advance.

1 hour? Was it really that long? And you give all this information for free? Subscribed. ;)
 

Burning Sounds

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Excellent video and very well presented (I worked as a camerman in TV studios and OBs for a number of years - some presenters are so natural and relaxed - Amir is one of them).

I do however, have to take issue with Amir's assertion in a response to a question about dipoles that all music played through dipoles has the same sound signature.

He said "Dipoles due to their design, can cast a very spacious stage which can be quite captivating. With the right music that works so well and beyond what you can get with a standard speaker. The issue I have with them is that they bring the same signature to everything you play. I don't want my rock and pop music to sound that way. To the extent your taste in music matches their capabilities, then they are an excellent choice. Otherwise, I don't think they are a replacement for normal monopole speakers."

I have no idea how many dipoles Amir has heard, but there is a big difference between how a large panel speaker like a Maggie sounds and a well-designed dynamic dipole like the Linkwitz LX521. I can agree that Maggies can sometimes have a tendency to make everything larger and at times easier on the ear than it should be. They can be quite beguiling and even make poorly recorded material sound quite nice.

LX521s are not like that. Rock sounds like rock, jazz sounds like jazz and reggae sounds like reggae. There is no same signature to everything that is played through LX521s.
 

alpha67

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Thanks for the excellent work, as always. I like your technical way of doing things, we can have a "physics" view of the product performance and then your personal observations and tweaks.
 

antcollinet

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Wonderful - can't wait till I can find a spare hour to sit and watch. :)
 

Hipster Doofus

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Boy you go away for a few days and someone who will remain nameless puts out a Manifesto on everything you ever needed to know about hi-fi….now all you need is some marketing folks to pretty it up and sell it. It will help put a few companies out of business and stand for a 1000 years.
 

Tom C

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Boy you go away for a few days and someone who will remain nameless puts out a Manifesto on everything you ever needed to know about hi-fi….now all you need is some marketing folks to pretty it up and sell it. It will help put a few companies out of business and stand for a 1000 years.
Wuhhhh?!?
 

Triliza

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That was a great video, I wouldn't have minded if it was 2 hours long. Now I can stop pretending (to myself) that I actually knew what most of those graphs were supposed to mean. Understanding how things work is a very rewarding experience. Thank you very much Amir for your time and effort.
 

JPA

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Great Video @amirm - if you do decide to do a talk at a future AXpona or similar event - a cut down version of this would surely go down well (with most open minded audiophiles) there :D

But a quick question, and I know you mentioned you think the step response is useless - but I am still curious as logically it would seem to me that an 'ideal' woofer would have a faster step response to be able to handle very 'fast' music, e.g. play something at 90db @ 200hz followed say 1 millisecond's later by being told to play something a 70db @ 500hz - if the woofer is still 'recovering' in time from playing the 200hz tone surely that would interfer with playing the 500hz tone correctly?
No. As long as the woofer's frequency response is flat from 200Hz to 500Hz it will be able to handle the transition from one tone to the other correctly. That's why the step response is useless. All the information you need is in the frequency response plot.
 

JeremyFife

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Thank you for a clear and illuminating video.
I resist watching videos usually, but I'm very glad I tried this one - really fantastic.
The explanation of frequency wavelength Vs driver size and the impact on FR and directivity was a 'light bulb' moment!
Thank you!
 
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